1. Technical Field
The present invention relates to a liquid ejecting head, a liquid ejecting head unit, and a liquid ejecting apparatus, in particular, relates to an ink jet recording head and an ink jet recording apparatus which discharge ink as liquid.
2. Related Art
In an ink jet recording head as a typical example of a liquid ejecting head, in general, ink is supplied from an ink cartridge as a liquid storage unit which is filled with ink to a head main body through an ink supply needle as an ink supply member and an ink supply path. The ink supply needle is inserted into the ink cartridge in a detachable manner or is arranged on the tip of a supply pipe such as a tube extended from the ink cartridge. The ink supply path is formed in a supply member such as a cartridge case by which the ink cartridge is held. Then, ink supplied to the head main body is discharged through a nozzle by driving a pressure generation unit such as a piezoelectric element provided on the head main body.
An ink jet recording head in which a filter is provided in order to eliminate discharge failure such as missing dot due to air bubbles or the like has been known as such ink jet recording head (for example, see JP-A-2009-220567). The filter is provided between the ink supply needle inserted into the ink cartridge and the cartridge case so as to remove air bubbles, dusts, and the like in ink.
However, in the configuration described in JP-A-2009-220567, in particular, when a filter is arranged in a flow path with an integral molding system in which double molding is performed so as to bond two parts to each other, there arises the following risk. That is, the filter is strained due to the difference in linear expansion coefficients between the two parts at the time of contraction of a molded resin to be partially swelled in some case. In this case, the filter wrinkles and sticks to an inner wall surface of the flow path at a downstream side of the filter or air bubbles easily accumulate between the wrinkled filter and the inner wall surface of the flow path at the downstream side of the filter. This causes a problem in that an effective area of the filter (area of on the filter through which liquid passes) is reduced.
It is to be noted that the above problem is caused not only in the ink jet recording head but also in a liquid ejecting head which ejects liquids other than ink.